[iMore Question]

How can I delete thousands of emails at once instead of one by one?

[Bigeric23]

If you have the option, use a browser to access your e-mail and remove them that way.

[Just_Me_D]

If the email has been moved to the trash folder then you can mass delete them by selecting "Edit" and then "Delete All". I am *assuming* you're using an iOS device. If, however, the email messages you want to delete are in your inbox, you're going to have to select them individually.